The subject matter disclosed herein relates generally to rotary wing aircraft and, more particularly, to a dual rotor, rotary wing aircraft.
A typical rotary wing aircraft, or helicopter, includes a main rotor assembly that provides lift for the aircraft. The main rotor assembly is secured to an airframe that often includes an extending tail. In many such aircraft, a tail rotor is located at the extending tail. In some other aircraft, an auxiliary propulsor is located at the extending tail. Some main rotor assemblies are configured as dual coaxial rotor systems, having an upper rotor assembly rotating in a first direction and a lower rotor assembly, coaxial to the upper rotor assembly and rotating in a second direction opposite the first direction. The aircraft is operational in a variety of modes, including take-off, cruise, landing, etc. Cruise mode refers to generally horizontal flight. During cruise, aircraft can reach speeds of above about 200 knots, with speed reaching up to about 250 knots. However, requirements and operational characteristics of the main rotor assemblies change as the aircraft begins to move through the air faster.